This invention relates to electrical power supplies. More particularly, it is concerned with electrical power supply apparatus which has low power consumption during standby operation and which provides electrical power for operating electrical apparatus only when required.
Many types of electrical apparatus operate infrequently or intermittently but must be ready on a standby basis for immediate operation when necessary. It is desirable that in the standby mode the apparatus consume very little power, particularly if it is battery powered. In many situations a simple manually-operated on-off switch can be used. However, in certain circumstances the apparatus may be in a remote location or must be turned on and/or off automatically in response to particular occurrences. Under conditions such as these the power supply must respond to an electrical signal to cause it to switch from the standby mode and provide operating potential for the apparatus.